The union claims passengers are paying “through the nose” for overcrowded services.

Research published this week found that the cost of rail travel has increased at more than twice the speed of wages since 2008. The TUC said fares have risen by 42 per cent over the past 10 years, while nominal weekly earnings have only grown by 18 per cent.

Many long-distance commuters will see the annual cost of getting to work increase by more than £150 next year.

The Department for Transport (DfT) uses the July Retail Prices Index (RPI) measure of inflation to determine the cap on the annual increase in regulated train fares, which comes into force every January.

Economists predict this will be around 3.5 per cent, but the exact figure will be released by the Office for National Statistics at 9.30am on Wednesday.

Campaigners argue it is unfair on passengers to use the RPI figure instead of the lower CPI measure of inflation.

RMT general secretary Mick Cash said: “Even if fares were pegged at the more modest CPI, these latest increases would still massively outstrip wages leaving the British passenger to pay through the nose to travel on rammed out and unreliable services.

“Meanwhile the rail companies, the majority of whom are foreign state owned, are using the British transport system as a cash cow to hold down their own domestic fares.”

Union leaders accused him of trying to cap pay rises in the industry. Labour said it was a “pathetic attempt” to shift the blame for Tory fares policies.

TUC analysis earlier this year showed that UK commuters spend up to six times more of their salary on rail fares than other European passengers.

The union organisation said that despite months of cancellations and delays, private train companies paid out at least £165 million in dividends to their shareholders, while the taxpayer handed £3.5 billion to these companies last year.